Nearly three-quarters of African American women and half of non-Hispanic White women of childbearing ages in the US are overweight or obese. About one-half (46%) of pregnant women exceed gestational weight gain recommendations. This problem is significant because excessive gestational weight gain is a strong risk factor for new or persistent obesity in women and increases a woman's risk for maternal complications. Furthermore, accumulating observational studies show that higher maternal gestational weight gain is associated with higher offspring birth weight, which persists in childhood, adolescence, and young adulthood. Novel intervention approaches have the potential to help overweight/obese financially disadvantaged women achieve healthy weight control during and after pregnancy and improve the health of their offspring. Our experienced multidisciplinary team will build on our promising R21 feasibility study to address the following specific aims: (1) examine the impact of a lifestyle intervention on gestational weight gain and postpartum weight loss in overweight and obese women, (2) examine the impact of the intervention on physical activity (PA), dietary intake, and quality of life (QOL), (3) examine race differences in total gestational weight gain, PA, dietary intake, and QOL; and (4) examine the impact of the intervention on offspring adiposity. Pregnant women (N=500) women, half African American and half White, will be recruited from seven obstetric clinics in Columbia, South Carolina and randomized to a lifestyle intervention (n=250) or standard care (n=250). The lifestyle intervention, grounded in Social Cognitive Theory, will target regular body weight self-monitoring and increasing PA and healthy dietary practices in pregnancy and postpartum. The lifestyle program will start within 15 weeks gestation and will continue through 6 months postpartum. In pregnancy, the intervention will consist of an individual session followed by 12 group-based sessions augmented with 12 podcasts, telephone follow-up, and social media support. In postpartum, the intervention will consist of an individual session (at 6 weeks) followed by 16 podcasts, telephone calls, and social media support until 6 months postpartum. All women will be assessed early in pregnancy (d15 weeks), at 32 weeks gestation, and at 6- and 12-mos postpartum, and offspring will be assessed at 6- and 12-mos. The study is innovative because it incorporates critical components that are missing in the larger literature. Namely, it is theoretically grounded, fully targets PA in addition to healthy eating, objectively measures PA, spans pregnancy to postpartum, includes racially and socioeconomically disadvantaged women who are overweight or obese, is powered to assess race differences in intervention effectiveness, considers the intergenerational linkage on childhood obesity, and integrates state-of-the-art behavioral strategies and approaches combined with innovative intervention channels (i.e., podcasts and social media support), all tailored to a unique population of women from a southeastern state with poor maternal and child health indicators.